C Y N , S H P A R G O T O H P L A T N E M A D N U F / a n g e M d r a h c i R ©
Experiment
11
Periodic Table and Periodic Law The halogens are, from left to right, solid iodine crystals, chlorine gas, and liquid bromine.
• To become become more more famil familiar iar with with the the periodi periodicc table table • To obser observe ve and to generalize generalize the the trends of various various atomic atomic properti properties es within within groups and periods of elements • To observe observe from experim experiment ent the trends trends of the chemica chemicall properties properties within within groups groups and periods of elements
Objectives
The following techniques are used in the Experimental Procedure:
Techniques
Similarities between the chemical and physical properties of elements were well known early in the nineteenth century. Several reports of grouping elements with like properties provided the background from which the modern periodic table finally evolved. However, it was in 1869, nearly simultaneously, when two masterful organizations of all known elements were revealed, one by Dmitri Mendeleev from Russia and the other from Lothar Meyer from Germany. From their independent research, their arrangement of the elements established the modern periodic table. Mendeleev showed that with the elements arranged in order of increasing atomic mass, their chemical properties recur periodically. When Meyer arranged the elements in order of increasing atomic mass, he found that their phys physical ical properties recur periodically. The two tables, however, were virtually identical. Because he drafted his table earlier in 1869 and because his table included “blanks” for yet-to-be-discovered elements to fit, Mendeleev is considered the “father” of the modern periodic table. In 1913, H. G. J. Moseley’s study of the X-ray spectra of the elements refined the periodic table to its current status: When the elements are arranged in order of increasing atomic number, atomic number, certain chemical and physical properties repeat periodically. See the inside back cover for a modern version of the periodic table. Photos of most all of the elements can be seen on www.periodicta www.periodictabletable.com bletable.com. The periodic table continues to expand with the synthesis of new elements (the transactinides 1), primarily at the Lawrence Livermore National Laboratory (California), the Joint Institute for Nuclear Research (Dubna, Russia), and the Institute for Heavy-Ion
Introduction
1
s e g a m I y t t e G a i v G I U / p u o r G s e g a m I l a s r e v i n U / o t o f v o S
Dmitri Mendeleev (1834–1907) Atomic number: the number of protons in the nucleus
en.wikipedia.org/wiki/Transactinide_element
Experiment 11 149
Research (Darmstadt, Germany). The most recent confirmation (in 2010) is the synthesis of element 117, an element that is one shy of completeing the seventh row of elements in the periodic table. (See Inside back cover.) Glenn T. Seaborg was the most prominent of the U.S. chemists involved in the synthesis of the transuranium elements. He was the recipient of the 1951 Nobel Prize in chemistry and was honored with the naming of element 106, Seaborgium. In the periodic table, each horizontal row of elements is a period each column column period,, and each family). is a group (or family ). All elements within a group have similar chemical and physical properties. Common terms associated with various sections of the periodic table are
s i b r o C / n n a m t t e B ©
Glenn T. Seaborg (1912–1999)
n o s t a W l e a h c i M
• Representa Representative tive elem elements ents:: Group Group “A” elem elements ents • Tra Transi nsitio tion n elemen elements: ts: Gro Groups ups 3–12 3–12 • Inner Inner-tra -transit nsition ion elements: elements: the lanthanid lanthanidee (atomic numbers numbers 58–71) 58–71) and actinide actinide (atomic numbers 90–103) series • Metal Metallic lic elements: elements: element elementss to the left of the “stair “stairstep step line” line” that runs runs diagodiagonally from B to At • Nonme Nonmetall tallic ic elements: elements: elemen elements ts to the right right of the “stairs “stairstep tep line” line” • Metal Metalloids loids:: elements elements that lie adjacent adjacent to the “stair “stairstep step line,” line,” excluding excluding Al • Post-t Post-transi ransition tion metals metals (or Poor Poor metals): metals): metals metals to the right right of the transiti transition on metals metals • Alk Alkali ali met metals als:: Group Group IA IA elemen elements ts • Alkal Alkaline ine earth meta metals: ls: Group IIA elem elements ents • Cha Chalco lcogen gens: s: Grou Group p VIA VIA eleme elements nts • Hal Haloge ogens: ns: Gro Group up VIIA VIIA ele elemen ments ts • Nob Noble le gases gases:: Group Group VIIIA VIIIA ele elemen ments ts • Rare earth earth metal metals: s: the lanth lanthanid anidee series series of eleme elements nts • Co Coin inag agee meta metals ls:: Cu, Cu, Ag, Ag, Au • Nob Noble le metal metals: s: Ru, Ru, Os, Rh, Rh, Ir, Pd, Pd, Pt, Ag, Ag, Au, Hg The periodicity of a physical property for a series of elements can be shown by plotting the experimental value of the property versus increasing atomic number. Physical properties studied in this experiment are the following.
Sodium metal is a shiny, but very reactive metal, typical of Group 1A elements.
Properties of Chlorine Atomic number 17 Molar mass 35.453 g/mol Density at 293 K 3.214 g/L Molar volume 22.7 cm3 /mol Melting point 172.22 K Boiling point 239.2 K Heat of fusion 3.203 kJ/mol Heat of va po poriz at ation 10.20 kJ/mol Firs Fi rstt ioni ioniza zati tion on ene energ rgy y 1251 12 51.1 .1 kJ/ kJ/mo moll Second Secon d ionization ionization energy energy 2297 2297.3 .3 kJ/mol kJ/mol Third Thi rd ioni ionizat zation ion ene energy rgy 382 3821.8 1.8 kJ/ kJ/mol mol Electronegativity 3.16 Electron affinity 349 kJ/mol Specific heat 0.48 J/g•K Heatt of ato Hea atomiz mizati ation on 121 kJ/ kJ/mol mol ato atoms ms Atomic radius 100 pm Ionic radius (– 1 ion) 167 pm Ther Th erma mall co cond ndu uct ctiivi vity ty 0.0 .01 1 J/ J/m• m•s• s•K K
150
• Ionizatio Ionization n energy (Figur (Figuree 11.1): the the energy energy required required to remove remove an electron electron from a gaseous atom • Atomi Atomicc radius radius (Figure (Figure 11.2): 11.2): the radius radius of an an atom of the the element element • Ele Electr ctron on affini affinity ty (Figu (Figure re 11.3) 11.3):: the energy released when a neutral gaseous atom accepts an electron • Densi Density ty (Figure (Figure 11.4): 11.4): the mass mass of a substan substance ce per unit unit volume volume For a very complete look at the properties and periodic trends of the elements, go to www.webelements.com. Other physical properties that show trends in groups and periods of elements are listed for chlorine in the table. Trends in the chemical properties of the boldface representative elements are studied in this experiment. d o i r e P
In this experiment, the relative acidic and/or basic strength of the hydroxides or oxides in the third period of the periodic table, the relative chemical reactivity of the halogens, and the relative solubility of the hydroxides and sulfates of magnesium, calcium, and strontium are observed through a series of qualitative tests. Observe closely the results of each test before generalizing your information. 2 2
For trends in chemical properties, go to http://en.wikipedia.org/wiki/category:chemistry
Periodic Table and Periodic Law
He ) l o m / J k (
Cs Ne
K
Rb
Na
Ar Kr
Li Xe
Figure 11.1 Ionization energies (kJ ( kJ /mol ) plotted against atomic number
Figure 11.2 Atomic radii (pm ( pm)) plotted against atomic number
Cl ) l o m / J k (
F
Br
I
Figure 11.3 Electron affinities (kJ ( kJ /mol ) plotted against atomic number, defined here as energy released
) 3
m c / g k (
Figure 11.4 Density (kg (kg/ /m3) plotted against atomic number
Procedure Overview: General trends in the physical properties of the elements are observed and studied in Figures 11.1–11.4. Experimental observations of the physical and chemical properties of a number of representative elements are made. Special attention is paid to the chemical properties of the halogens. Ask your instructor about the working relationship, individuals or partners, for Part A. For Parts B, C, and D, perform the experiment with a partner. At each circled Sheet. superscript 1–18 in the procedure, stop and record your observation on the Report the Report Sheet. Discuss your observations with your lab partner and your instructor.
Experimental
Figures 11.1 through 11.4 plot the experimental data of four physical properties of the elements as a function of their atomic number. While actual values cannot be readily obtained from the graphical data, the periodic trends are easily seen. All values requested for the analyses of the graphical data need only be given as your “best possible” estimates from the figure. The periodic trends for the elements are analyzed through a series of questions on Report Sheet. Sheet. the Report the
A. Periodic Trends in Physical Properties (Dry Lab)
Prepare a hot water bath for Part B.3.
B. The Appearance of Some Representative Elements
1. Sample Sampless of elemen elements. ts. Samples of the third period representative elements sodium, magnesium, aluminum, silicon, and sulfur are on the reagent table. Note that the Na metal is stored under a nonaqueous liquid to prevent rapid air oxidation. Polish
Procedure
Experiment 11 151
the Mg and Al metal strips with steel wool for better viewing. Record your observations on the Report the Report Sheet. Sheet. Since some chlorine, bromine, and iodine vapors may escape the test tubes in Parts B.2–4 and C.1–3, you may want to conduct the experiments in the fume hood. Consult with your laboratory instructor. 2. Chlo Chlori rine ne.. In a clean, 150-mm test tube, place 2 mL of a 5% sodium hypochlorite, NaClO, solution (commercial laundry bleach) and 10 drops of cyclohexane. Agitate the mixture (Figure 11.5). Which layer is the cyclohexane layer? 3 Add ~10 drops of 6 M HCl. (Caution: (Caution: 6 M HCl is very corrosive. Wash immediately from the skin. ) Swirl or agitate the mixture (with a stirring rod) so that the HCl mixes with the NaClO solution. Note the color of the chlorine in the cyclohexane layer. Record your observation. 1 Do not discard—save for Part C.1. 3. Brom Bromin ine. e. In a second, clean test tube, place 2 mL of 3 M KBr solution and 3 drops of cyclohexane. cyclohexane. Add 5–10 5–10 drops of 8 M HNO3. (Caution: ( Caution: HNO3 attacks skin tissue; flush the affected area immediately with water. ) Agitate or swirl the mixture so that the 8 M HNO3 mixes with the KBr solution. Place the test tube in a hot water bath to increase the reaction rate. Note the color of the bromine in the cyclohexane layer. Record, 2 but do not discard—save for Part C.2. 4. Iodi Iodine ne.. Repeat Part B.3 in a third test tube, substituting 3 M KI for 3 M KBr. Record. Compare the appearance of the three halogens dissolved in the cyclohexane. 3 Save for Part C.3.
Figure 11.5 Shake the contents of the test tube with the little finger.
C. The Chemical Properties of the Halogens
4
For Parts C.1–3, six clean, small ( ~75-mm), test tubes are required. Summarize your Sheet. Number each test tube observations at the conclusion of Part C.3 on the Report Sheet. (Figure 11.6). Place the test tubes into a test tube rack. 1. Chlorine Chlorine and its reactions reactions with with bromide bromide and iodide ions. ions. Clean two small test tubes; add a pinch (on the end of a spatula) of solid KBr to the first test tube and a pinch of KI to the second. Use a dropping pipet to withdraw the chlorine/cyclohexane layer from Part B.2 and add an (approximately) equal portion to the two test tubes. Swirl or agitate the solution, observe, and record. Write appropriate net ionic equations. 4
Pinch: a solid mass about the size of a grain of rice
2. Bromine Bromine and its reactio reactions ns with chloride chloride and and iodide ions. ions. Add a pinch of solid NaCl to a third, small clean test tube and a pinch of KI to the fourth test tube. Use a dropping pipet to withdraw the bromine/cyclohexane layer from Part B.3 and add an (approximately) equal portion to the two test tubes. Swirl or agitate the solution, observe, and record. Write appropriate net ionic equations. 5 3. Iodine Iodine and its reactions reactions with with chloride chloride and bromide bromide ions. Add a pinch of solid NaCl to a fifth, small clean test tube and a pinch of KBr to the sixth test tube. Use a dropping pipet to withdraw the iodine/cyclohexane layer from Part B.4 and add an (approximately) equal portion to the two test tubes. Swirl or agitate the solution, observe, and record. Write appropriate net ionic equations. 6 What can you conclude about the relative chemical reactivity of the halogens?
Figure 11.6 Six labeled test tubes to test the relative reactivity of the halogens c fi i t n e i c S r e h s i F o m r e h T f o y s e t r u o C
Disposal: Dispose of the waste water/halogen mixtures in the Waste Halogens container.
3 4
152
Mineral oil, or any colorless cooking oil, may be substituted for cyclohexane. A 24-well plate may be substituted for the small test tubes.
Periodic Table and Periodic Law
Twelve clean, small ( ~75-mm) test tubes 5 are required for the chemical reactions observed in Part D. Number each test tube (Figure 11.7). Place the test tubes into the test tube rack.
D. The Chemical Properties of the Halides
1. The reactions reactions of the the halides halides with various various metal metal ions. Label 12 clean, small test tubes and transfer the following to each: • • • •
Test tubes tubes 1, 2, 2, and 3: a pinch of NaF and and 10 drops drops of water water Test tubes tubes 4, 5, 5, and 6: a pinch of NaCl and 10 drops drops of of water water Test tubes tubes 7, 8, 8, and 9: a pinch of KBr and and 10 drops drops of water water Test tubes tubes 10, 10, 11, and and 12: a pinch pinch of of KI and 10 drops drops of water water
Appendix G
a. Slowly add 10 drops of 2 M Ca(NO3)2 to test tubes 1, 4, 7, and 10. Observe closely and over a period of time. Vary the color of the background of the test tubes for observation. 7 b. Slowly add 10 drops of 0.1 M AgNO3 to test tubes 2, 5, 8, and 11. Observe. After about 1 minute, add 10 drops of 3 M NH3. 8 c. Add 1 drop of 6 M HNO3 (Caution! (Caution!)) and slowly add 10 drops of 0.1 M Fe(NO3)3 to test tubes 3, 6, 9, and 12. Observe closely and over a period of time. 9 d. Summarize your observations of the chemical activity for the halides with the Ca 2+, Ag+, and Fe3+ ions on the grid on the Report the Report Sheet. Sheet.
Figure 11.7 Twelve labeled test tubes to test the reactivity of the halides.
Disposal: Dispose of the waste water/halogen mixtures in the Waste Halogens container. CLEANUP: Rinse the test tubes with copious amounts of tap water and twice with deionized water. Discard the rinses in the sink.
Demonstration Only. Wrap a pea-sized piece of sodium metal 1. Sodi Sodium um..6 Instructor Demonstration in aluminum foil. Fill a 200-mm Pyrex test tube with water, add 2 drops of phenolphthalein,7 and invert the test tube in a beaker of water (Figure 11.8, page 154). Set the beaker and test tube behind a safety shield. Punch 5–10 holes with a pin in the aluminum foil. With a pair of tongs or tweezers, place the wrapped sodium metal in the mouth of the test tube, keeping it under water. What is the evolved gas? Test the gas by holding the mouth of the inverted test tube over a Bunsen flame. 10 A loud pop indicates the presence of hydrogen gas. Account for the appearance of the color change in the solution. 11
E. Chemical Reactivity of Some Representative Elements
5
A 24-well plate may be substituted for the small test tubes. Calcium metal can be substituted for sodium metal with the same results. 7 Phenolphthalein is an acid–base indicator; it is colorless in an acidic solution but pink in a basic solution. 6
Experiment 11 153
2. Mag Magnes nesium ium and and aluminu aluminum. m.
200-mm test tube
with acid . Polish 5-cm strips of Mg and Al metal; cut 5-mm pieces and a. Reaction with place them into separate small test tubes. Add ~10 drops of 3 M HCl to each test tube. (Caution: (Caution: Do not allow the HCl to touch the skin. Wash the affected area immediately. ) Which metal reacts more rapidly? 12 What is the gas that is evolved? 13
b. Reaction with base. Add (and count) drops of 6 M NaOH to each test tube until a precipitate appears. Continue to add NaOH to the test tube containing the aluminum ion until a change in appearance occurs. Add the same number of drops to the test tube containing the magnesium ion. Record your observations. 8 14 Add drops of 6 M HCl until both solutions are again colorless. Observe closely as each drop is added. Record and explain.
Phenolphthalein
z e d n a n r e 600-mL H beaker y e r T / n a r e B . A o J
3. Solub Solubilit ilities ies of alkaline alkaline-eart -earth h cations. cations. a. Solubility of the hydroxides. Place 10 drops of 0.1 M MgCl2, 0.1 M CaCl2, and 0.1 M Sr(NO3)2 in three separate, clean test tubes. Count and add drops of 0.050 M NaOH until a cloudiness appears in each test tube. Predict the trend in the solubility of the hydroxides of the Group 2A cations. 15
Sodium metal wrapped in aluminium foil
b. Solubility of the sulfates. Place 10 drops of 0.1 M MgCl2, 0.1 M CaCl2, and 0.1 M Sr(NO3)2 in three separate, clean test tubes. Count and add drops of 0.10 M Na2SO4 until a cloudiness appears in each test tube. Predict the trend in the solubility of the sulfates of the Group 2A cations. 16
Figure 11.8 Collection of hydrogen gas from the reaction of sodium and water
4. Sulfurous Sulfurous acid and and sulfuric sulfuric acid. Because of the possible evolution of a foulsmelling gas, you may want to conduct this part of the experiment in the fume hood. Consult with your instructor. a. Place a double pinch of solid sodium sulfite, Na 2SO3, into a clean small or medium-sized test tube. Add 5–10 drops of 6 M HCl. Test the evolved gas with wet blue litmus paper. Write a balanced equation for the reaction. 17 b. Repeat the test, substituting solid sodium sulfate, Na 2SO4, for the Na2SO3. Account for any differences or similarities in your observations. 18
Disposal: Discard the solutions as directed by your instructor. CLEANUP: Rinse the test tubes twice with tap water and with deionized water. Discard the rinses in the sink. The Next Step
The periodic trends for many chemical and physical properties of the elements can be found on the Internet. There are many Web sites, and the data are plotted for many properties using various coordinates. A first reference is www.acs.org. Seek a data plot, for example, of atomic radii versus ionization energy or for any properties as listed in the table for chlorine in the Introduction.
8
Magnesium ion precipitates as magnesium hydroxide, Mg(OH)2; aluminum ion also precipitates as the hydroxide, Al(OH)3 but redissolves in an excess of OH to produce Al(OH)4 , the aluminate ion. –
154
Periodic Table and Periodic Law
–
Experiment 11 Prelaborato Prelaboratory ry Assignment Periodic Table and Periodic Law Date __________ Lab Sec. ______ Name ________________________________ ____________________________________________ ____________ Desk No. __________ 1. On the blank periodic table, clearly indicate six of the following element sections, using your own color code. a. Representative elements h. Alkali metals b. Transition elements i. Alkaline earth metals c. Inner-transiti j. Halogens Inner-transition on elements d. Chalcogens k. Noble gases e. Coinage metals l. Noble metals f. Metalloids m. Lanthanide series g. Post-transition metals n. Actinide series Periodic Table
2. Sketch in the stairstep line that separates the metals from the nonmetals on the periodic table. 3. Identify the atomic numbers of the elements that would be called the transactinide elements.
Experiment 11 155
4. Classify each of the following elements according to the categories of elements identified in question 1: a. Magne Magnesium sium _____ __________ __________ _____
f. Po Pota tasssi sium um
Plut uton oniu ium m b. Pl
____ __ ____ ____ ____ ____ ____ ___ _
Elemen mentt 118 118 ___ ______ ______ ______ ______ ___ g. Ele
c. Argon
_______________
h. Silver
_______________
Zirc rcon oniu ium m d. Zi
____ __ ____ ____ ____ ____ ____ ___ _
i. Lead
_______________
Bro omine e. Br
_______________
j. Titanium
_______________
____ __ ____ ____ ____ ___ ___ ____ __
5. Refer to Figure 11.1. Which of the following has the highest ionization energy? or ox oxygen a. carbon or
______________________
c. mag magnes nesium ium or alu alumin minum um
______ ___ ______ ______ ______ ______ ______ ____ _
b. ph phos osph phor orus us or or sulf sulfur ur
____ __ ____ ____ ____ ____ ____ ____ ____ ____ ____ __
d. ma magn gnes esiu ium m or calc calciu ium m
____ __ ____ ____ ____ ____ ____ ____ ____ ____ ____ __
6. Refer to Figure 11.2. Which of the following has the largest atomic radius? a. carbon or or ox oxygen
______________________
magnes nesium ium or alumi aluminum num c. mag
______ ___ ______ ______ ______ ______ ______ ____ _
b. ph phos osph phor orus us or or sulf sulfur ur
____ __ ____ ____ ____ ____ ____ ____ ____ ____ ____ __
d. ma magn gnes esiu ium m or calc calciu ium m
____ __ ____ ____ ____ ____ ____ ____ ____ ____ ____ __
Compare your answers for questions 5 and 6. What correlation can be made?
7. a. Proceeding from left to right across a period of the periodic table, the elements become (more, less) metallic. b. Proceeding from top to bottom in a group of the periodic table, the elements become (more, less) metallic. 8. Consider the generic equation for the reaction of the halogens, X 2 and Y2: X2(g) + 2Y–(aq) —› 2X–(aq) + Y2(g) Is X2 or Y2 the more reactive halogen? Explain.
9. a. Experimental Procedure, Part B.2. What commercially available compound is used to generate Cl 2 in the experiment?
b. Experimental Procedure, Part B. The observation for the presence of the elemental form of the halogens is in a solvent other than water. Identify the solvent.
c. Experimental Procedure, Part E.3. Identify the tests used to observe the periodic trends in the chemical properties of the alkaline–earth metal ions.
156
Periodic Table and Periodic Law
Experiment 11 Report Sheet Periodic Table and Periodic Law Date __________ Lab Sec. ______ Name ________________________________ ____________________________________________ ____________ Desk No. __________ A. Perio Periodic dic Trends Trends in Physical Physical Properties Properties (Dry Lab) Lab) Consult with your laboratory instructor as to the procedure and schedule for submitting your responses to the following questions about periodic trends. 1. Figure 11.1: Graphical data for the ionization energies of the elements show sawtooth trends across the periods of the elements. a. Locate the noble gas group of elements. What appears to be the periodic trend in ionization energies down the noble gas group (i.e., with increasing atomic number)? b. Scanning the graphical data for elements adjacent to and then further removed from the halogens, what general statement can summarize the trend in the ionization energies when moving down a group of elements? c. Which element has the highest ionization energy? d. What general statement can summarize the trend in the ionization energies when moving across a period of elements? 2. Figure 11.2: Graphical data for the atomic radii of the elements show generally decreasing trends across a period of elements. The noble gases are an anomaly. a. Which group of elements has the largest atomic radii? b. Moving down a group of elements (increasing atomic number), what is the general trend for atomic radii? c. Which element has the largest atomic radius? d. What general statement can summarize the correlation of ionization energies to atomic radii for the elements? 3. Figure 11.3: Graphical data for the electron affinities of the elements show a number of irregularities, but a general increasing trend in values exists across a period of elements. a. Which group of elements has the highest electron affinities? b. Is the trend in electron affinities repetitive for Periods 2 and 3? Cite examples. c. Which element has the highest electron affinity? d. Is there a correlation of electron affinities to atomic radii for the elements? If so, what is it? Cite examples. 4. Figure 11.4 shows repeated trends in density for the periods of elements. a. What is the general trend in densities for Periods 2 and 3? b. What is the trend in the densities moving down a group of elements? c. Which section of the periodic table (see Introduction) has elements with greater densities? d. Which element has the greatest density?
Experiment 11 157
B. The Appearanc Appearancee of Some Representat Representative ive Elements Elements Element
Physical State ( g, g, l, s) s)
Physical Appearance and Other Observations
Color
Na
__________________
_______________________________________
___________________
Mg
__________________
_______________________________________
___________________
Al
__________________
_______________________________________
___________________
Si
__________________
_______________________________________
___________________
S8
____ __ ____ ___ ___ ____ ____ ____ ____ ___ _
___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ __
____ __ ___ ___ ____ ____ ___ ___ ____ ____ ___ _
1
Cl2
____ __ ____ ___ ___ ____ ____ ____ ____ ___ _
___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ __
____ __ ___ ___ ____ ____ ___ ___ ____ ____ ___ _
2
Br2
____ __ ____ ___ ___ ____ ____ ____ ____ ___ _
___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ __
____ __ ___ ___ ____ ____ ___ ___ ____ ____ ___ _
3
I2
____ __ ____ ___ ___ ____ ____ ____ ____ ___ _
___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ __
____ __ ___ ___ ____ ____ ___ ___ ____ ____ ___ _
C. The Chemica Chemicall Properties Properties of the the Halogens Halogens Observations in the cyclohexane layer Cl2 4
Br2 5
KCl
XX*
KBr
______________
KI
______________ ______________
I2 6
Net Ionic Equation(s)
______________ ______________ __________________________________________ XX
______________ __________________________________________ XX
__________________________________________
*No reaction mixture.
What can you conclude about the relative reactivity of Cl 2, Br2, and I2?
D. The Chemica Chemicall Properties Properties of the the Halides Halides 1. The Reaction Reactionss of the Halides Halides with with Various Various Metal Ions Ions Describe the appearance of each mixture in tubes 1–12. 7
(Test tube no.) NaF(aq)
NaCl(aq) (Test tube no.) NaBr(aq) (Test tube no.)
158
(1)
8
AgNO3( aq) aq) (2)
9
Fe(NO3)3( aq) aq) (3)
______ ___ ______ ______ ______ ______ ______ ______ ______ ____ _ ___ ______ ______ ______ ______ ______ ______ ______ ______ ____ _ ___ ______ ______ ______ ______ ______ ______ ______ ______ _____ __
(Test tube no.)
NaI(aq)
Ca(NO3)2( aq) aq)
(4)
(5)
(6)
______ ___ ______ ______ ______ ______ ______ ______ ______ ____ _ ______ _________ ______ ______ ______ ______ ______ ______ ____ _ ______ _________ ______ ______ ______ ______ ______ ______ _____ __ (7)
(8)
(9)
______ ___ ______ ______ ______ ______ ______ ______ ______ ____ _ _______ __________ ______ ______ ______ ______ ______ ______ ___ _____ ________ ______ ______ ______ ______ ______ ______ ______ ___ (10)
(11)
(12)
____ __ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ __ ___ _____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ __ ___ _____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ __
Periodic Table and Periodic Law
From the observed data, answer the following questions. a. Which of the metal fluorides are insoluble? ______________________ b. Which of the metal chlorides are insoluble? ______________________ c. Which of the metal bromides are insoluble? ______________________ d. Which of the metal iodides are insoluble? ______________________
E. Chem Chemical ical Reactivi Reactivity ty of Some Representati Representative ve Elements Elements 1. Sod Sodium ium (or Cal Calciu cium) m) a.
10
Name the gas evolved in the reaction of Na with water: _______________
b.
11
What is produced from the reaction of Na with water as indicated by the action of phenolphthalein?
c. Write the chemical equation for the reaction of Na with water:
2. Mag Magnes nesium ium and and Alumi Aluminum num a.
12
Which metal reacts more rapidly with HCl? _______________
13
What is the gas that is evolved when Mg and Al react with HCl? _______________
b. Reaction of metal ion with NaOH 14
M N 6 M NaOH
M NaOH Excess 6 M NaOH
Mg2+ (d (drrop opss to prec preciipi pita tatte)
___ __ ___ ____ ____ ___ ___ ____ __
____ __ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ___ _
Al3+ (dr dro ops to pr prec eciipi pittat ate) e)
___ __ ___ ____ ____ ___ ___ ____ __
____ __ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ___ _
Observations
c. Explain the differences in chemical behavior of the magnesium and aluminum hydroxides. Use chemical equations in your discussion.
3. Solub Solubilit ilities ies of Alkaline Alkaline-Ear -Earth th Cations Cations Observations
15
16
0.050 M NaOH 0.050 M NaOH
0.10 M Na 0.10 M Na2SO4
Mg2+ (dr drop opss to to pre preci cipi pittat atee)
____ __ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ___ _
___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ __
Ca2+ (d (drrop opss to pr prec eciipi pittat ate) e)
____ __ ____ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ __
___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ __
Sr2+ (d (dro rops ps to pr prec ecip ipiita tate te))
____ __ ____ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ____ ___ __
____ __ ____ ___ ___ ____ ____ ____ ____ ____ ___ ___ ____ ____ ____ ____ ___ _
List the hydroxide salts in order of increasing solubility: ______________
<
List the sulfate salts in order of increasing solubility: _______________
_______________ < _______________
<
_______________ < _______________
What can you conclude about the general trend in solubilities of the Group IIA metal hydroxides and sulfates?
Experiment 11 159
4. Sulfurous Sulfurous Acid and Sulfuri Sulfuricc Acid Acid 17 a. What does the litmus test indicate about the chemical stability of sulfurous acid?
b. What is the gas that is generated? _______________ c. Write an equation for the decomposition of sulfurous acid.
d.
18
What does the litmus test indicate about the chemical stability of sulfuric acid? _______________
e. What chemical property differentiates sulfurous acid from sulfuric acid?
Laboratory Questions Circle the questions that have been assigned. 1. Part A. Considering the trends in ionization energies, would you expect sodium or potassium to be more reactive? Explain. 2. Part A. Considering the trends in atomic radii, would you expect cesium or radon to have the larger radius? Explain. 3. Part A. Compare the ionization energies of sodium and rubidium and then compare the electron affinities of chlorine and iodine. Which of the following chemical combinations of the elements would be the most exothermic—Na and Cl, Na and I, Rb and Cl, or Rb and I? Explain. 4. Part C. Chlorine is used extensively as a disinfectant and bleaching agent. Without regard to adverse effects or costs, would bromine be a more or less effective disinfectant and bleaching agent? Explain. 5. Part C. Is fluorine gas predicted to be more or less reactive than chlorine gas? Explain. 6. Part C. Not much is known of the chemistry of astatine. Would you expect astatine to more or less reactive than iodine? Explain. 7. Part E.2. Predict the reactivity of silicon metal relative to that of magnesium and aluminum. Explain. 8. Part E.3. a. Is barium hydroxide predicted to be more or less soluble that Ca(OH) 2? Explain. b. Is barium sulfate predicted to be more or less soluble that CaSO 4? Explain. 160
Periodic Table and Periodic Law
